The present invention relates to a support and withdrawal mechanism for milking clusters and consists of a stationary vertical main column, a support pipe that can be moved up and down inside it and has a horizontal articulated extension arm for holding the milking cluster attached to it, and a flexible tensioning element attached at one end to the last member of the extension arm and at the other end to a retraction device.
A support and withdrawal mechanism of this type is known for example from German OS No. 2 518 326, wherein the milking cluster is suspended from the last member of the horizontal extension arm. The support pipe can be moved axially up and down inside the main column to a proper level in relation to the udder of a cow by means of a motor and threaded spindle. Another motor retracts the flexible tensioning element and removes the extension arm and milking cluster from the vicinity of the udder when a subsiding flow of milk indicates that milking is coming to an end. Since many of the cows, however, are not completely milked out at this point of time, milking must be continued manually or mechanically.
It has turned out to be practical in follow-up milking to exert a tension on the milking cultser that slopes toward the front legs of the cow. A sloping tension of this type cannot be exerted with the known mechanism because the support pipe can only be moved up and down. Another drawback is that the horizontal extension arm remains at the height at which it has been positioned during the milking process and does not follow the varying height of the udder.
A device that allows tension to be exerted on the milking cluster with the extension arm adjusting itself to the varying height of the udder is known from German OS No. 2 654 245. Nevertheless, aside from the need for expensive controls in that device to adjust the extension arm to the height of the udder, the extension arm can still be moved only up and down. Sloping tension is only possible when the force exerted by the extension arm does not act under the center of the udder but eccentrically to it. The anatomy and momentary position of the animal thus prevents precise definition of the direction of tension.